A 17th-century manuscript written by Sir Isaac Newton that was held in a private collection for decades is being placed online, offering a fascinating glimpse into the work of the celebrated physicist.

The rediscovered document is Newton’s handwritten copy of a manuscript by alchemist George Starkey detailing the preparation of “sophick mercury,” viewed as an essential element in producing the so-called “philosopher’s stone” for turning base metals into gold.

Philadelphia-based nonprofit the Chemical Heritage Foundation bought the manuscript in February and is placing digital images and transcriptions of the text into an online database for study.

“The significance of the manuscript is that it helps us understand Newton's alchemical reading--especially of his favorite author -- and gives us evidence of one more of his laboratory procedure,” explained James Voelkel, curator of rare books at the Othmer Library of Chemical History, in a statement emailed to FoxNews.com. Voelkel notes that there are scores and scores of Newton's alchemical manuscripts by Newton, who wrote an estimated 1,000,000 words of notes on alchemy during his lifetime. “Our manuscript is just one among these,” he added.

Starkey, writing in Latin as Eirenaeus Philalethes, published a text on the preparation of sophick mercury in 1678. Newton’s manuscript, however, is a copy of another Starkey manuscript, not the printed text – it may even predate the published version. “We can tell this from Newton’s comments in square brackets that either expand abbreviations in the other manuscript or correct it,” Voelkel explained.

Newton also wrote unrelated notes on the distillation of iron ore on the back of the manuscript bought by the Chemical Heritage Foundation. The notes “may well be laboratory notes of a process Newton had tried or was thinking of trying,” said Voelkel. “Like many of us, when Newton needed a place to jot something down, he would sometimes just turn over a manuscript and write on the blank page on the back.”

Voelkel, who is also resident scholar at the Beckman Center for the History of Chemistry, said that the terms alchemy and chemistry were basically synonymous in Newton’s time. “It was not until around the time of Newton's death that professional chemists ‘rebranded’ chemistry, relegating gold-making to an enterprise now derogatorily labeled ‘alchemy’ and keeping the respectable parts in ‘chemistry’,” he said.